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123 lines
3.1 KiB
123 lines
3.1 KiB
/* |
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* Driver for ST M41T94 SPI RTC |
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* |
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* Taken from the Linux kernel drivier: |
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* Copyright (C) 2008 Kim B. Heino |
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* |
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* Adaptation for U-Boot: |
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* Copyright (C) 2009 |
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* Albin Tonnerre, Free Electrons <[email protected]> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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*/ |
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#include <common.h> |
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#include <rtc.h> |
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#include <spi.h> |
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static struct spi_slave *slave; |
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#define M41T94_REG_SECONDS 0x01 |
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#define M41T94_REG_MINUTES 0x02 |
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#define M41T94_REG_HOURS 0x03 |
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#define M41T94_REG_WDAY 0x04 |
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#define M41T94_REG_DAY 0x05 |
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#define M41T94_REG_MONTH 0x06 |
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#define M41T94_REG_YEAR 0x07 |
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#define M41T94_REG_HT 0x0c |
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#define M41T94_BIT_HALT 0x40 |
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#define M41T94_BIT_STOP 0x80 |
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#define M41T94_BIT_CB 0x40 |
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#define M41T94_BIT_CEB 0x80 |
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int rtc_set(struct rtc_time *tm) |
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{ |
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u8 buf[8]; /* write cmd + 7 registers */ |
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int ret; |
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if (!slave) { |
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slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS, |
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CONFIG_M41T94_SPI_CS, 1000000, |
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SPI_MODE_3); |
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if (!slave) |
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return -1; |
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} |
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spi_claim_bus(slave); |
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buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */ |
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buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec); |
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buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min); |
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buf[M41T94_REG_HOURS] = bin2bcd(tm->tm_hour); |
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buf[M41T94_REG_WDAY] = bin2bcd(tm->tm_wday + 1); |
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buf[M41T94_REG_DAY] = bin2bcd(tm->tm_mday); |
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buf[M41T94_REG_MONTH] = bin2bcd(tm->tm_mon + 1); |
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buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB; |
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if (tm->tm_year >= 100) |
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buf[M41T94_REG_HOURS] |= M41T94_BIT_CB; |
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buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100); |
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ret = spi_xfer(slave, 64, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END); |
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spi_release_bus(slave); |
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return ret; |
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} |
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int rtc_get(struct rtc_time *tm) |
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{ |
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u8 buf[2]; |
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int ret, hour; |
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if (!slave) { |
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slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS, |
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CONFIG_M41T94_SPI_CS, 1000000, |
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SPI_MODE_3); |
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if (!slave) |
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return -1; |
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} |
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spi_claim_bus(slave); |
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/* clear halt update bit */ |
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ret = spi_w8r8(slave, M41T94_REG_HT); |
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if (ret < 0) |
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return ret; |
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if (ret & M41T94_BIT_HALT) { |
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buf[0] = 0x80 | M41T94_REG_HT; |
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buf[1] = ret & ~M41T94_BIT_HALT; |
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spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END); |
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} |
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/* clear stop bit */ |
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ret = spi_w8r8(slave, M41T94_REG_SECONDS); |
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if (ret < 0) |
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return ret; |
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if (ret & M41T94_BIT_STOP) { |
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buf[0] = 0x80 | M41T94_REG_SECONDS; |
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buf[1] = ret & ~M41T94_BIT_STOP; |
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spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END); |
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} |
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tm->tm_sec = bcd2bin(spi_w8r8(slave, M41T94_REG_SECONDS)); |
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tm->tm_min = bcd2bin(spi_w8r8(slave, M41T94_REG_MINUTES)); |
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hour = spi_w8r8(slave, M41T94_REG_HOURS); |
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tm->tm_hour = bcd2bin(hour & 0x3f); |
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tm->tm_wday = bcd2bin(spi_w8r8(slave, M41T94_REG_WDAY)) - 1; |
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tm->tm_mday = bcd2bin(spi_w8r8(slave, M41T94_REG_DAY)); |
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tm->tm_mon = bcd2bin(spi_w8r8(slave, M41T94_REG_MONTH)) - 1; |
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tm->tm_year = bcd2bin(spi_w8r8(slave, M41T94_REG_YEAR)); |
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if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB)) |
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tm->tm_year += 100; |
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spi_release_bus(slave); |
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return 0; |
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} |
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void rtc_reset(void) |
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{ |
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/* |
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* Could not be tested as the reset pin is not wired on |
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* the sbc35-ag20 board |
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*/ |
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}
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